Carbon nanofibers with hybrid crystalline-amorphous silicon nanoparticles: high-rate capable lithium-ion battery

With the rapid commercialization of electric vehicles, fast-charging high-energy batteries are the need of the hour. Developing such high-rate capable batteries need advanced materials beneficial for providing high energy densities and long-lasting cycle life. Silicon, one of the high energy anode materials with a theoretical capacity of 4200 mAh g(- 1), is prone to volume expansion and degrades the battery performance. Herein, we utilize the hybrid silicon structure (crystalline and amorphous) prepared by a large-scale cryomilling process and embed them in carbon nanofibers to combat these challenges. We have further investigated the effect of the changes in carbon-fiber characteristics (e.g., diameter and morphology) on silicon structure. From the perspective of high-rate capable battery applications, electrochemical performance has been studied for mid-to-high current density. The ensemble constituting silicon/carbon nanofiber exhibits excellent charge-discharge rate capability over current densities (4-160 A g(electrode)(- 1)). A specific capacity of 3050 mAh g(- 1) was calculated for the first cycle, corresponding to 73% of the theoretical value, with charge-discharge stability for over 100 cycles.

Automated summary

With the rapid commercialization of electric vehicles, there is a growing need for fast-charging high-energy batteries. However, silicon, one of the potential anode materials, faces challenges such as volume expansion and degradation of battery performance. In this study, a hybrid silicon structure embedded in carbon nanofibers was developed to address these challenges. The silicon/carbon nanofiber ensemble exhibited excellent charge-discharge rate capability and stability for over 100 cycles.